CN111810598B

CN111810598B - Method and system for an electric drive arrangement

Info

Publication number: CN111810598B
Application number: CN202010283908.3A
Authority: CN
Inventors: A·T·布拉默; M·D·库克
Original assignee: Dana Heavy Vehicle Systems Group LLC
Current assignee: Dana Heavy Vehicle Systems Group LLC
Priority date: 2019-04-11
Filing date: 2020-04-13
Publication date: 2024-01-02
Anticipated expiration: 2040-04-13
Also published as: DE102020204653A1; US11198356B2; US12036866B2; US20200324639A1; CN111810598A; US20220009333A1

Abstract

Various methods and systems are provided for a drive arrangement for a vehicle, the drive arrangement comprising: a housing; a double planetary gear set partially or fully housed within the housing; an input shaft selectively engaged with the double planetary gear set; a first clutch assembly coupled to the input shaft and selectively engaged with the double planetary gear set; a second clutch assembly coupled to the input shaft and selectively engaged with the double planetary gear set; and a sliding spline coupled to the input shaft and selectively engaged with the double planetary gear set. The double planetary gear set includes: the first sun gear, the second sun gear, the first set of planet gears, the second set of planet gears, the planet gear carrier, and the ring gear, wherein each member of the double planetary gear set is lockable, thereby providing three different gear ratios.

Description

Method and system for an electric drive arrangement

Cross Reference to Related Applications

The present application claims priority from U.S. provisional patent application No. 62/832,472 entitled "drive arrangement and shift method for the drive arrangement (A Drive Arrangement and Shifting Method for the Drive Arrangement)" filed on day 4 and 11 of 2019. The present application also claims priority from U.S. provisional patent application No. 62/895,620, entitled "drive arrangement and shift method for the drive arrangement (A Drive Arrangement and Shifting Method for the Drive Arrangement)" filed on 4, 9, 2019. The applications listed above are incorporated by reference in their entirety for all purposes.

Technical Field

Embodiments of the subject matter disclosed herein relate to an electric drive arrangement and a shift method.

Background

The electric motor may be used as a single or supplemental source of rotational energy to move the vehicle over the ground, thereby reducing or eliminating reliance on an internal combustion engine, and thus reducing or eliminating fuel costs, pollution, complexity, and other drawbacks. Heavy trucks require motors with high torque capabilities to handle the large weights and loads encountered by these vehicles. A gearbox may be connected to these motors to provide a range of functions for the motors and the vehicle. However, known gearboxes typically use conventional hydraulic clutches, which occupy a large amount of space on the vehicle and require complex hydraulic systems and control devices to operate.

Disclosure of Invention

In an embodiment, a system includes a drive arrangement for a vehicle, the drive arrangement comprising: a housing; a double planetary gear set partially or fully housed within the housing; an input shaft selectively engaged with the double planetary gear set; a first clutch assembly coupled to the input shaft and selectively engaged with the double planetary gear set; a second clutch assembly coupled to the input shaft and selectively engaged with the double planetary gear set; and a sliding spline coupled to the input shaft and selectively engaged with the double planetary gear set. The double planetary gear set includes: the first sun gear, the second sun gear, the first set of planet gears, the second set of planet gears, the planet gear carrier, and the ring gear, wherein each member of the double planetary gear set is lockable, thereby providing three different gear ratios. An input shaft is coupled to the motor and configured to receive torque from the motor.

It should be understood that the brief description above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. This is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the appended claims. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Drawings

The disclosure will be better understood by reading the following description of non-limiting embodiments, with reference to the accompanying drawings, in which:

FIG. 1 schematically illustrates a vehicle having a hybrid propulsion system;

FIG. 2 is a cross-sectional side view of a portion of an electric drive arrangement according to one embodiment of the present disclosure;

FIG. 3 is an enlarged cross-sectional side view of the transmission of the electric drive arrangement of FIG. 2;

FIG. 4 is a schematic front view of gears of the transmission that make up the electric drive arrangement of FIG. 2;

FIG. 5 is a method for shifting the electric drive arrangement of FIGS. 2-4;

FIG. 6 is a cross-sectional side view of a portion of an electric drive arrangement according to a second embodiment of the present disclosure; and

fig. 7 is a method for shifting the electric drive arrangement of fig. 6.

Fig. 2-4 and 6 are shown to scale generally, but other relative dimensions may be used.

Detailed Description

An Electric Vehicle (EV) may employ a single gear to drive the wheels because the motor has a wider RPM window in which it may operate efficiently, and the motor is energy efficient throughout the RPM window, as compared to a conventional internal combustion engine. In this way, the EV need not be used for a specific RPM range during low-speed running or acceleration, and almost instantaneous torque can be generated from zero rotation speed. Accordingly, a gear ratio for the electric vehicle axle assembly is selected that includes a balance between acceleration and maximum speed. If the gear ratio is too low, the EV may accelerate very rapidly, but be limited to a lower maximum speed. Alternatively, if the transmission ratio is relatively high, the transmission ratio may be optimal for the highest speed, but the acceleration will be limited. Therefore, it is desirable for EVs to achieve increased speeds without affecting acceleration. Furthermore, different consumer applications (e.g., racing applications, heavy duty truck applications) may require or benefit from an electric axle assembly having multiple gear ratios.

In this way, the gearbox may be connected to the electric motor, thereby permitting the customer to select from more than one gear ratio during operation of the vehicle. For example, a first gear ratio may be selected to increase launch (launch) performance, and a second gear ratio may be selected to more efficiently drive at high speeds. Gearboxes employed by motors for heavy truck applications generally use conventional hydraulic clutches to shift between different gear ratios. However, hydraulic clutch systems take up a lot of packaging space and require complex hydraulic systems to operate. Accordingly, it is desirable to be able to achieve high energy density from Electric Vehicle (EV) motors and gearboxes using compact and high output power components for a range of applications including heavy truck applications.

Thus, according to embodiments disclosed herein, a three-speed electric drive arrangement is provided that utilizes two clutches and one sliding spline coupling to shift between different gear ratios. The drive arrangement comprises a gearbox with a Ravigneaux or a Ravigneaux type gear set, wherein different parts of the Ravigneaux or the Ravigneaux type gear set are kept in stationary positions during different operating conditions to produce three different gear ratios. A single synchronizer clutch and one-way clutch coupled between the housing and the carrier assembly provides power flow from all three gear ratios. The sliding spline coupling is used for neutral engagement because synchronization is not required when the vehicle is stopped. Both the synchronizer clutch and the one-way clutch use separate electromechanical actuators. By utilizing a simple clutch assembly as is typically found on manual transmissions, packaging space for the electric drive arrangement can be minimized while still maintaining a high torque carrying capacity. Furthermore, the cost, weight and complexity of the gearbox may be reduced as the use of hydraulic clutches and hydraulic actuation is eliminated.

It is within the scope of the present disclosure and as a non-limiting example, that the electric drive arrangement and shift (gear change) method for the assemblies disclosed herein may be used in automotive, off-road, all-terrain, and structural applications. As non-limiting examples, the electric drive arrangements and shift methods for the assemblies disclosed herein may also be used in passenger vehicle, EV, hybrid electric vehicle, commercial vehicle, autonomous vehicle, semi-autonomous vehicle, and/or heavy-duty vehicle applications. FIG. 1 is an example of a hybrid vehicle propulsion system that may include embodiments of the electric drive arrangement disclosed herein. A first embodiment of the electric drive arrangement is shown in fig. 2 to 4, and a second embodiment of the electric drive arrangement is shown in fig. 6. Methods for shifting the first and second embodiments of the electric drive arrangement are provided in fig. 5 and 7, respectively.

FIG. 1 illustrates an exemplary vehicle propulsion system 100 that may include the electric drive arrangement of the present disclosure. The vehicle propulsion system 100 includes an electric motor 110. The motor 110 may be coupled to the transmission 104. The transmission 104 may be a manual transmission, an automatic transmission, or a combination thereof. In addition, various additional components may be included, such as a torque converter, and/or other gears such as a final drive unit, etc. The transmission 104 is shown coupled to a drive wheel 106 in contact with a road surface 108. Accordingly, the motor 110 may be drivingly coupled to the drive wheels 106 via the transmission 104. The depicted connection between the motor 110, transmission 104, and drive wheels 106 represents the transfer of mechanical energy from one component to another, while the connection between the motor 110 and the energy storage device 114 may represent the form of transferred electrical energy. The transmission 104 may also be used in the implementation of a hybrid vehicle.

The vehicle propulsion system 100 may employ a variety of different modes of operation depending on the operating conditions encountered by the vehicle propulsion system 100. For example, under selected operating conditions, the electric motor 110 may propel the vehicle via the drive wheels 106. During other operating conditions, the motor 110 may be operated to charge (energize) the energy storage device 114 (e.g., battery, capacitor, flywheel, pressure vessel, etc.). For example, the electric motor 110 may receive wheel torque from the drive wheels 106, wherein the electric motor 110 may convert kinetic energy of the vehicle to electrical energy for storage at the energy storage device 114. This operation may be referred to as regenerative braking of the vehicle. Thus, in some embodiments, the motor 110 may provide the function of a generator. However, in other embodiments, the generator 120 may instead receive wheel torque from the drive wheels 106, wherein the generator 120 may convert kinetic energy of the vehicle into electrical energy for storage at the energy storage device 114. In some embodiments, the energy storage device 114 may be configured to store electrical energy that may be provided to other electrical loads onboard the vehicle (beyond the motor 110), including cabin heating and air conditioning, engine starting, headlights, cabin audio and video systems, and the like. As a non-limiting example, the energy storage device 114 may include one or more batteries and/or capacitors.

Control system 122 may be in communication with one or more of motor 110, energy storage device 114, generator 120, and/or additional components of vehicle propulsion system 100. For example, the control system 122 may receive sensory feedback information from one or more of the motor 110, the energy storage device 114, and the generator 120. Further, in response to the sensory feedback, the control system 122 may send control signals to one or more of the motor 110, the energy storage device 114, and the generator 120. Control system 122 may receive an indication of an output of the vehicle propulsion system requested by a driver from a driver of the vehicle (e.g., via a pedal position sensor communicatively coupled to an accelerator and/or brake pedal).

The energy storage device 114 may periodically receive electrical energy from an external energy source 116 that is external to the vehicle (e.g., not part of the vehicle). As a non-limiting example, the vehicle propulsion system 100 may be configured as a plug-in electric vehicle (PEV), whereby electrical energy may be provided from the external energy source 116 to the energy storage device 114 via an electrical energy transfer cable. The external energy source 116 may be disconnected from the energy storage device 114 when the vehicle propulsion system 100 is operated to propel the vehicle. Control system 122 may identify and/or control the amount of electrical energy stored at the energy storage device, which may be referred to as a state of charge (SOC). In other embodiments, electrical energy may be received wirelessly from an external energy source 116 at the energy storage device 114. For example, the energy storage device 114 may receive electrical energy from an external energy source 116 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. As such, it should be appreciated that any suitable method may be used for charging the energy storage device 114 from a power source that does not form part of the vehicle. In this way, the motor 110 may propel the vehicle by utilizing the energy source.

The vehicle propulsion system 100 may include an electric drive arrangement according to the present disclosure. As such, the transmission 104 may include planetary gear sets, such as Ravigneaux or Ravigneaux type gear sets, that are used to produce three different gear ratios. The transmission 104 may utilize two clutches and one sliding spline coupling to hold different portions of the gear set stationary, thereby shifting between gear ratios as commanded by signals output from the control system 122 in response to user input. In this way, packaging space for the electric drive arrangement may be minimized while still maintaining a high torque carrying capacity.

Fig. 2 is a cross-sectional side view of a portion of a (car) axle assembly 200 of a vehicle including a first embodiment of an electric drive arrangement 202. The bridge assembly 200 includes a prime mover, such as an electric motor 204, coupled to a drive arrangement 202. In some embodiments, the prime mover may be a power source fueled by a non-electrical energy source (e.g., hydrocarbon, solar, and/or pneumatic energy sources). The drive arrangement 202 includes a final drive assembly 206, a double planetary gear set 208, and a clutch mechanism 210. The double planetary gear set 208 and the clutch mechanism 210 may be contained within a housing 244.

The drive arrangement 202 may receive power from the motor 204 via an input shaft 216 extending through the drive arrangement 202. A motor shaft 228 may extend from the motor 204 and be connected to the input shaft 216. The connection between the input shaft 216 and the motor shaft may thereby allow power to be transferred from the motor 204 to the drive arrangement 202. The input shaft 216 may be connected to the motor shaft 228 via a coupling, spline, joint, or another suitable connection mechanism capable of transmitting torque from the motor 204 to the input shaft 216 via the motor shaft 228. Power transferred to the input shaft 216 may then be transferred to the double planetary gear set 208 via a first sun gear 232 coupled to the input shaft 216 and surrounding the input shaft 216.

Double planetary gear set 208 includes a first sun gear 232, a second sun gear 234, a first set of planet gears 236, a second set of planet gears 238, a ring gear 240, and a planet gear carrier 242. In some embodiments, the double planetary gear set 208 may be a ravigneaux or ravigneaux type gear set. As shown in front view 400 of double planetary gear set 208 shown in FIG. 4, first sun gear 232 may be selectively engaged with second sun gear 234. The second sun gear 234 may have a larger diameter and more teeth than the first sun gear 232. Each of the first and second sets of planet gears 236, 238 may include two planet gears. For example, the first set of planet gears 236 includes a first inner planet gear 402 and a first outer planet gear 404. The second set of planet gears 238 includes a second outer planet gear 406 and a second inner planet gear 408. In some embodiments, one or both of the first and second sets of planet gears 236, 238 may have more than two gears. For example, in some embodiments, the first set of planet gears 236 may have three gears and the second set of planet gears 238 may have four gears.

The first sun gear 232 may be directly coupled to and concentric with the first set of planet gears 236 via interaction with the first inner planet gears 402. For example, the teeth of the first sun gear 232 may mesh with the teeth of the first inner planet gears 402. Similarly, the second sun gear 234 may be directly coupled to and concentric with the second set of planet gears 238 via interaction with the second outer planet gears 406. Further, first set of planet gears 236 can be indirectly coupled to second set of planet gears 238 via a coupling interaction between first outer planet gear 404 and second outer planet gear 406 and ring gear 240. For example, the teeth of first outer planet gears 404 and second outer planet gears 406 may mesh with inner teeth 410 of ring gear 240. In addition, external teeth 412 of ring gear 240 may mesh with teeth of pinion gear 212 that forms final drive assembly 206, as further described below. In some embodiments, ring gear 240 may mesh with more than one gear of each of the first and second sets of planet gears 236, 238.

Ring gear 240 may radially surround first sun gear 232, second sun gear 234, first set of planet gears 236, second set of planet gears 238, and planet gear carrier 242. The planet carrier 242 may be rotatably coupled to and provide support for one or more gears of the first set of planet gears 236 and one or more gears of the second set of planet gears 238. For example, the planet carrier 242 may be connected to the central bore 414 of the first inner planet gear 402 and the central bore 416 of the second inner planet gear 408. Accordingly, the first and second sets of planet gears 236, 238 may rotate about the first and second sun gears 232, 234 using torque provided to the double planetary gear set 208 via the input shaft 216. The torque may then be transferred from first set of planet gears 236 and/or second set of planet gears 238 to ring gear 240, where it is then transferred to final drive assembly 206.

Returning now to FIG. 2, a final drive assembly 206 may be located between the motor 204 and a double planetary gear set 208. Final drive assembly 206 may include a pinion gear 212 drivingly engaged with a ring gear 214. Pinion gears 212 of final drive assembly 206 may be coupled with ring gear 240 of double planetary gear set 208. Accordingly, torque transferred from the motor 202 to the input shaft 216 may be transferred through the double planetary gear set 208 (e.g., connected to the first sun gear 232 via the input shaft 216) and from the ring gear 240 of the double planetary gear set 208 to the pinion gear 212 of the final drive assembly 206.

Pinion 212 may then transfer torque to ring gear 214. Ring gear 214 is further coupled to differential 218. The differential 218 may be drivingly connected to a first axle 220 and a second axle 222 extending therefrom. The first axle 220 may be connected to a first wheel 224 and the second axle 222 may be connected to a second wheel 226. Accordingly, the configuration of final drive assembly 206 may change the direction of drive arrangement 202 and transfer torque power from drive arrangement 202 to differential 218. The differential 218 may then distribute torque to the first axle 220 and the second axle 222, rotating each of the first wheel 224 and the second wheel 226, thereby propelling the vehicle.

Thus, by selectively engaging different portions of the double planetary gear set 208, the vehicle may be operated in three separate gear ratios. These three gear ratios can be advantageously used to increase the medium speed performance of the vehicle, which many vehicles typically spend a significant amount of time in this case. Furthermore, since the motor and transmission can be maintained in the peak efficiency region, three gear ratios can improve overall efficiency. Different portions of the double planetary gear set 208 may be selectively engaged using the clutch mechanism 210. The clutch mechanism 210 may be communicatively coupled to a control system (e.g., the control system 122 of fig. 1). The clutch mechanism 210 may include a first clutch assembly 246, a second clutch assembly 248, and a sliding spline 250. In response to a user input, the control system may send a signal that causes one or more of the several clutches comprising the clutch mechanism 210 to selectively engage a portion of the double planetary gear set 208, as described further below.

Fig. 3 is an enlarged cross-sectional side view of the drive arrangement 202, showing the clutch mechanism 210 in more detail. The first clutch assembly 246 is disposed adjacent the second sun gear 234, the second clutch assembly 248 is selectively coupled with the planet carrier 242, and the sliding spline 250 is disposed adjacent to and coupled with the first sun gear 232. In some embodiments, the first clutch assembly 246 may be interposed between the double planetary gear set 208 and the sliding spline 250 on the drive arrangement 202.

The first clutch assembly 246 includes a first shift fork 302 and a first actuator 304. In a preferred embodiment, the first clutch assembly 246 may be a synchronizer clutch. In some embodiments, the first clutch assembly 246 may be a wet clutch, a dry clutch, a dog clutch (dog clutch), or an electromagnetic clutch. In some embodiments, the first actuator 304 may be an electrical actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electromechanical actuator, and/or an electromagnetic actuator. In response to a user input, the first shift fork 302 and the first actuator 304 may engage the first clutch assembly 246 to couple the second sun gear 234 to the housing 244, thereby preventing rotation of the second sun gear 234.

The second clutch assembly 248 may be a conventional clutch or a selectable one-way clutch. The second clutch assembly 248 may be coupled to the housing 244 and the planet carrier 242. In response to a user input, the second clutch assembly 248 may couple the planet carrier 242 to a portion of the housing 244, such as the grounded (fixed) housing member 312, thereby preventing the planet carrier 242 from rotating (turning). In some embodiments, a second clutch assembly 248 is interposed between the first clutch assembly 246 and the double planetary gear set 208 on the drive arrangement 202.

The sliding spline 250 includes a second shift fork 306 and a second actuator 308. In some embodiments, the second actuator 308 may be an electrical actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electromechanical actuator, and/or an electromagnetic actuator. In some embodiments, the sliding spline 250 may be a sliding non-synchronized clutch or a neutral clutch. The second actuator 308 may be operably configured to allow the second shift fork 306 to cause axial movement of the sliding spline 250 along an axis 310 of the drive arrangement 202. Accordingly, in response to user input, sliding spline 250 may move along axis 310, thereby selectively engaging first sun gear 232 and/or second sun gear 234.

Fig. 5 is a flow chart illustrating a method 500 for shifting the drive arrangement 202 illustrated in fig. 2 to 4. The method 500 is described with reference to the systems and components described above with respect to fig. 1-4, but may also be performed with other systems/components (e.g., motor of heavy trucks, motor of machines) without departing from the scope of the present disclosure. The method 500 may be performed in accordance with instructions stored in a non-transitory memory of a computing device, such as a control system of a vehicle (e.g., the control system 122 of fig. 1). The control system may include a Central Processing Unit (CPU) to execute instructions stored in memory.

At 502, the method 500 may include shifting to a first gear ratio by coupling the first sun gear 234 to the motor shaft 228 via axial movement of the sliding spline 250. The sliding spline 250 may be coupled to the first sun gear 232 via a spline connection. The sliding spline 250 is splined to the first sun gear 232 only during periods when the vehicle is not in operation. Thus, even if the motor shaft 228 is allowed to rotate, no torque is transferred through the double planetary gear set 208. During operation, the sliding spline 250 moves axially along an axis 310 of the drive arrangement 202 (e.g., away from the neutral clutch position) via the second shift fork 306 and the second actuator 308. The axial movement couples the sliding spline 250 between the first sun gear 232 and the input shaft 216, thereby rotatably coupling the first sun gear 232 to the input shaft 216, and thus, the first sun gear 232 may be indirectly coupled to the motor shaft 228 via the sliding spline 250 and receive torque transmitted from the motor shaft 228. The sliding spline 250 is additionally coupled to the input shaft 216, and the input shaft 216 is coupled to the motor shaft 228 and receives torque from the motor shaft 228.

The coupling of the first sun gear 232 to the motor shaft 228 may result in a first gear ratio in the forward direction. When the first sun gear 232 is coupled to the motor shaft 228, the planet carrier 242 may be coupled to a portion of the housing 244 via the second clutch assembly 248, thereby preventing movement of the planet carrier 242. Thus, in the first gear ratio, torque is transferred from the first sun gear 232 to the first and second sets of planet gears 236, 238, from the first and second sets of planet gears 236, 238 to the ring gear 240, from the ring gear 240 to the final drive assembly 206, and from the final drive assembly 206 to the first and second wheels 224, 226.

Once operating in the first gear ratio, the vehicle may be shifted to the second gear ratio in the forward direction by coupling the second sun gear 234 to a portion of the housing 244 of the drive arrangement 202 at 504. The second sun gear 234 may be coupled to a portion of the housing 244 (such as a grounded housing member 312) to prevent rotation of the second sun gear 234. In some embodiments, the first shift fork 302 and the first actuator 304 may engage the first clutch assembly 246 to couple the second sun gear 234 to the housing 244. In some embodiments, the first shift fork 302 and the first actuator 304 may engage the sliding spline 250 to couple the second sun gear 234 to the housing 244. Thus, in the second gear ratio, torque is transferred from the first sun gear 232 to the first set of planet gears 236, from the first set of planet gears 236 to the planet carrier 242, from the planet carrier 242 to the ring gear 240, from the ring gear 240 to the final drive assembly 206, and from the final drive assembly 206 to the first and second wheels 224, 226.

Once operating in the second gear ratio, the vehicle may be shifted in the forward direction to the third gear ratio by disengaging the second sun gear 234 from the housing 244 and coupling the second sun gear 234 to the first sun gear 232 at 506. In some embodiments, the first shift fork 302 and the first actuator 304 may engage the sliding spline 250 to disengage the second sun gear 234 from a portion of the housing 244 and couple the second sun gear 234 with the first sun gear 232. In some embodiments, the first shift fork 302 and the first actuator 304 may engage the first clutch assembly 246 to disengage the second sun gear 234 from a portion of the housing 244 and couple the second sun gear 234 with the first sun gear 232. Because of the coupling of the second sun gear 234 with the first sun gear 232, the entire double planetary gear set 208 may rotate together, thus providing a 1: a third gear ratio of 1. In some embodiments, the rotation of the motor 228 may be reversed to produce each of the reverse first, second, and third gear ratios for the drive arrangement 202.

The decision to use method 500 to shift gears may depend on several factors. For example, the most basic shift control may be based on vehicle speed, which allows for a smooth torque transition from one gear ratio to the next. More advanced switching controls may include logic-based transitions based on vehicle speed, throttle position, brake position, and/or prospective prediction techniques. Under certain driving conditions it is possible to switch directly from first gear to third gear or vice versa. Typically, a shift from first gear to third gear (and vice versa) is only performed under very low loads and accelerations, so that a smooth gear shift is maintained and operation in the highest efficiency region is possible.

Fig. 6 is a cross-sectional side view of a portion of a second embodiment of an electric drive arrangement 600 according to the present disclosure. The drive arrangement 600 includes a clutch mechanism 608 and a double planetary gear set 602 housed within a housing 610. The double planetary gear set 602 includes a first sun gear 604, a second sun gear 606, a first set of planet gears 612, a second set of planet gears 614, a planet gear carrier 616, and a ring gear 618. In some embodiments, the double planetary gear set 602 may be a ravigneaux gear set or a ravigneaux gear set.

The first sun gear 604 is selectively engageable to the second sun gear 606. The second sun gear 606 may have a larger diameter and more teeth than the first sun gear 604. The first sun gear 604 may be directly coupled to and concentric with the first set of planet gears 612. The first sun gear 604 may be interposed between a first set of planet gears 612 and a second set of planet gears 614. The first set of planet gears 612 may be coupled to the second set of planet gears 614. The ring gear 618 may radially surround the first sun gear 604, the second sun gear 606, the first set of planet gears 612, the second set of planet gears 614, and the planet gear carrier 616. The planet carrier 616 may be rotatably coupled to and provide support for one or more gears of the first set of planet gears 612 and one or more gears of the second set of planet gears 614.

The clutch mechanism 608 of the electric drive arrangement 600 includes a first clutch assembly 620 and a second clutch assembly 622, but without sliding splines (e.g., as compared to the electric drive arrangement 202). The first clutch assembly 620 is disposed proximate the second sun gear 606 and is selectively coupled to the planet carrier 616. The first clutch assembly 620 is also interposed between the second clutch assembly 622 and the second sun gear 606. In some embodiments, each of the first clutch assembly 620 and the second clutch assembly 622 may be synchronizer clutches. In some embodiments, the first clutch assembly 620 and the second clutch assembly 622 may be wet clutches, dry clutches, tooth clutches, or electromagnetic clutches.

In response to the actuator, the first clutch assembly 620 may move from the starting position along an axis 624 of the electric drive arrangement 600 toward the planet carrier 616. Axial movement of the first clutch assembly 620 may cause the planet carrier 616 to be coupled to the housing 610, thereby preventing rotation of the planet carrier 616. Further, axial movement of the first clutch assembly 620 away from the planet carrier 616 (e.g., to a point between the starting and initial positions) may cause the planet carrier 616 to decouple from the housing 610 and the second sun gear 606 to couple to the housing 610. Accordingly, the planet carrier 616 may be free to rotate and the second sun gear 606 may be locked in the rest position. Axial movement of the first clutch assembly 620 back to the starting position, and axial movement of the second clutch assembly 622 along the axis 624 toward the planet carrier 616, may result in the second sun gear 606 being rotatably coupled to the first sun gear 604.

Thus, in contrast to the first embodiment of the electric drive arrangement 202, in the drive arrangement 600, the first clutch is responsible for the first gear ratio and the second gear ratio, while the second clutch is responsible for the third gear ratio. To achieve the first forward gear ratio, the actuator mechanism and shift fork translate the sliding spline clutch sleeve toward the planet carrier assembly to ground (fix) the planet carrier assembly. To achieve the second forward gear ratio, the same mechanism moves the same spline clutch back through its neutral position and then further so as to then ground the second larger sun gear. To achieve the third forward gear ratio, the first spline clutch sleeve is moved back to its center neutral position by the actuator and fork mechanism. The second actuator mechanism and shift fork assembly then move the second sliding spline clutch sleeve from its neutral center position toward the transmission, thus coupling the small sun gear and the large sun gear together.

Fig. 7 is a flowchart illustrating a method 700 for shifting the drive arrangement 600 shown in fig. 6. The method 700 is described with reference to the systems and components described above with respect to fig. 1-4 and 6, but may also be implemented with other systems/components (e.g., motor of heavy trucks, motor of machines) without departing from the scope of the present disclosure. Method 700 may be performed in accordance with instructions stored in a non-transitory memory of a computing device, such as a control system of a vehicle (e.g., control system 122 of fig. 1).

At 702, the method 700 may include shifting to a first gear ratio by coupling the planet carrier 616 to a portion of the housing 610 via the first clutch assembly 620. In response to the actuator 625, the first clutch assembly 620 may be moved along the axis 624 of the drive arrangement 600 from a starting position toward the planet carrier 616. For example, an electromechanical actuator may be used. The movement of the actuator may be determined by an electronic control unit such that the motor rotates a screw drive coupled to the cam and lever mechanism. The axial movement is converted into a rotational movement of the shift rail. This rotation allows the fork to pivot and produce an axial displacement at a fork pad that is coupled to the sliding spline clutch sleeve. Axial movement of the first clutch assembly 620 may couple the planet carrier 616 to a portion of the housing 610, thereby preventing rotation of the planet carrier 616. When the planetary gear carrier 616 is held in the rest position, a first gear ratio in the forward direction is established. The coupling of the planetary gear carrier 616 to a portion of the housing 610 results in a first gear ratio being established in the forward direction. Thus, in a first gear ratio, torque may be transferred from an electric motor (e.g., electric motor 204 of fig. 2) to an input shaft (e.g., input shaft 216 of fig. 2), from the input shaft to first sun gear 604, from first sun gear 604 to first and second sets of planet gears 612, 614, from first and second sets of planet gears 612, 614 to ring gear 618, and from ring gear 618 to a final drive assembly (e.g., final drive assembly 206 of fig. 2), where torque may be further transferred to wheels of a vehicle, thereby propelling the vehicle.

Once operating in the first gear ratio, the vehicle may be shifted to the second gear ratio by decoupling the planet carrier 616 from the housing 610 and coupling the second sun gear 606 to the housing 610 at 704. The planet carrier 616 may be uncoupled by axial movement of the first clutch assembly 620 of the actuator away from the planet carrier 616. The first clutch assembly 620 may move rearward but not to the starting position, thereby decoupling the planet carrier 616 from the housing 610 and engaging and securing the second sun gear 606 to a portion of the housing 610. Engagement of the second sun gear 606 with a portion of the housing 610 results in a second gear ratio being established in the forward direction. Thus, in the second gear ratio, torque may be transferred from the motor to the input shaft, from the input shaft to the first sun gear 604, from the first sun gear to the first set of planet gears 612, from the first set of planet gears 612 to the planet carrier 616, from the planet carrier 616 to the ring gear 610, and from the ring gear 610 to the final drive assembly, where the torque may be further transferred to the wheels of the vehicle, thereby propelling the vehicle.

Once operating in the second gear ratio, the vehicle may be shifted to the third gear ratio by decoupling the second sun gear 606 from the housing 610 and coupling the second sun gear 606 to the first sun gear 604 at 706. In response to the actuator, the first clutch assembly 620 moves back to the starting position and the second clutch assembly 622 moves along the axis 624 toward the planet carrier 616, thereby causing the coupling of the second sun gear 606 with the first sun gear 604. The coupling of the second sun gear 606 with the first sun gear 604 results in a third gear ratio being formed in the forward direction. Thus, torque may be transferred from the motor to the input shaft, from the input shaft to the entire double planetary gear set 602, and from the ring gear 610 of the double planetary gear set 602 to the final drive assembly, where torque may be further transferred to the wheels of the vehicle, thereby propelling the vehicle. In some embodiments, the rotation of the motor may be reversed to create a reversed first gear ratio, second gear ratio, and third gear ratio for the drive arrangement 600.

The decision to shift using method 700 may depend on several factors. For example, the most basic shift control may be based on vehicle speed, which allows for a smooth torque transition from one gear ratio to the next. More advanced switching controls may include logic-based transitions based on vehicle speed, throttle position, brake position, and/or prospective prediction techniques. Under certain driving conditions it is possible to switch directly from first gear to third gear and vice versa. Typically, the shift from first gear to third gear (and vice versa) is only done under very low loads and accelerations, so that smooth gear transitions are maintained and operation in the highest efficiency region is possible.

Each of the drive arrangements 202, 600 disclosed herein is operably configured to use an electric motor to provide a level of shift synchronization. Due to the rapid response time of the motor, the motor may generate positive and/or negative torque to reduce the load on each of the double planetary gear sets 208, 602 during the shift event. Thus, the need to switch between three gear ratios using hydraulic clutches is eliminated, thereby reducing the cost, weight, and complexity of the transmission of the drive arrangements 202, 600.

It is to be understood that the various embodiments described in this specification and shown in the drawings are merely exemplary embodiments, which illustrate the inventive concepts as defined in the claims. As a result, it is to be understood that the various embodiments described and illustrated may be combined to form the inventive concepts defined in the appended claims. In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. It should be noted, however, that the present invention may be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

In a first embodiment, a drive arrangement has: a dual planetary gear set, comprising: a first sun gear; a second sun gear, wherein the diameter of the second sun gear is greater than the diameter of the first sun gear; a first set of planet gears, wherein the first set of planet gears are coupled with the first sun gear; a second set of planet gears, wherein the second set of planet gears is coupled to the second sun gear and to the first set of planet gears; and a ring gear radially surrounding the first and second sets of planet gears. The drive arrangement further comprises: a first clutch assembly disposed proximate to the second sun gear, wherein the first clutch assembly includes a shift fork and an actuator; a second clutch assembly; and a sliding spline disposed adjacent to the first sun gear.

In a second embodiment, a drive arrangement has: a dual planetary gear set, comprising: a first sun gear; a second sun gear, wherein the diameter of the second sun gear is greater than the diameter of the first sun gear; a first set of planet gears, wherein the first set of planet gears are coupled with the first sun gear; a second set of planet gears, wherein the second set of planet gears is coupled to the first set of planet gears; and a ring gear radially surrounding the first and second sets of planet gears. The drive arrangement further comprises: a first clutch assembly disposed adjacent to the second sun gear; and a second clutch assembly disposed proximate to the first clutch assembly, wherein the first clutch assembly is interposed between the second clutch assembly and the second sun gear. The first sun gear may be attached to the motor.

In some embodiments, the double planetary gear set of the drive arrangement may be a ravigneaux gear set or a ravigneaux gear set. In some embodiments, the first sun gear of the double planetary gear set of the drive arrangement may be coupled to the electric motor.

In a first embodiment, a method for a shift drive arrangement may include: connecting the first sun gear to the motor shaft by axially moving the sliding spline; coupling a second sun gear to a portion of a housing of the planetary gear set; and coupling the second sun gear with the first sun gear such that the entire double planetary gear set rotates together.

In a second embodiment, a method for a shift drive arrangement includes: coupling a planet carrier to a portion of the housing via a first clutch assembly; coupling the second sun gear to a portion of the housing by switching the first clutch assembly; and coupling the second sun gear with the first sun gear by switching the first clutch assembly and the second clutch assembly such that the entire double planetary gear set rotates together.

In some embodiments, the shift method for the drive arrangement described herein results in three gear ratios being formed in the forward direction. In some embodiments, three gear ratios for the drive arrangement in the reverse direction may be obtained by reversing the rotation of the motor.

Fig. 2 to 4 and 6 show example constructions with relative positioning of the individual components. If shown as being in direct contact with or directly coupled to each other, such elements may be referred to as being in direct contact with or directly coupled to each other, respectively, in at least one example. Similarly, elements shown as being continuous with or adjacent to each other may be continuous with or adjacent to each other, respectively, in at least one example. As an example, components placed in coplanar contact with each other may be referred to as coplanar contacts. As another example, in at least one example, elements positioned spaced apart from one another with only spacing therebetween and no other components may be so called. As yet another example, elements shown above/below each other, on opposite sides of each other, or left/right of each other may be so called with respect to each other. Further, as shown in the figures, in at least one example, the topmost element or position of an element may be referred to as the "top" of a component, while the bottommost element or position of an element may be referred to as the "bottom" of a component. As used herein, top/bottom, upper/lower, above/below may be relative to a vertical axis of the drawings and are used to describe the positioning of elements in the drawings relative to each other. Thus, in one example, elements shown above other elements are located vertically above the other elements. As yet another example, the shape of an element depicted in the figures may be referred to as having such a shape (e.g., such as circular, rectilinear, planar, curved, rounded, chamfered, angled, etc.). Further, in at least one example, elements shown intersecting each other may be referred to as intersecting elements or intersecting each other. Still further, in one example, elements shown as being within or outside of another element may be so-called.

In this way, the drive arrangement described herein provides three gear ratios that may be advantageously utilized by a user of an electric or hybrid vehicle. Furthermore, a shift synchronizer of the type of a single manual transmission can be used for shifting between all three gear ratios. Thus, the cost, weight and complexity of the gearbox of the drive arrangement may be reduced and alternatives are provided for the current demand for hydraulic clutches for switching between gear ratios of the electric vehicle.

As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to "one embodiment" of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising," "including," or "having" one or more elements having a particular property may include other such elements not having that property. The terms "include" and "wherein (in white)" are used as plain language equivalents to the respective terms "comprising" and "wherein (white)". Furthermore, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements or a particular order of location on their objects.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A drive arrangement comprising:

a housing;

a double planetary gear set partially or fully housed within the housing, the double planetary gear set comprising a first sun gear, a second sun gear, a first set of planet gears, a second set of planet gears, a planet carrier, and a ring gear;

an input shaft selectively engaged with the double planetary gear set, the input shaft in mechanical communication with the electric motor;

a first clutch assembly coupled to the input shaft and selectively engaged with the double planetary gear set; and

A second clutch assembly coupled to the input shaft and selectively engaged with the double planetary gear set,

wherein each member of the double planetary gear set is lockable, thereby providing three different gear ratios;

a first gear ratio is obtained by coupling the planet carrier to a portion of the housing via axial movement of the first clutch assembly, which includes moving the first clutch assembly from a starting position toward the planet carrier in response to a first actuator.

2. The drive arrangement of claim 1, wherein a second gear ratio is obtained by decoupling the planet carrier from the housing and coupling the second sun gear to the housing via axial movement of the first clutch assembly, the axial movement of the first clutch assembly including moving the first clutch assembly from the planet carrier toward the starting position but not to the starting position.

3. The drive arrangement of claim 2, wherein a third gear ratio is obtained by decoupling the second sun gear from the housing and connecting the second sun gear with the first sun gear via axial movement of the first clutch assembly and the second clutch assembly, the axial movement of the first clutch assembly comprising moving the first clutch assembly back to the starting position, and the axial movement of the second clutch assembly comprising moving the second clutch assembly toward the planet carrier.